Hauling machines are utilized in various industries to transport a payload from one location to another. In order to operate such machines efficiently, it is desirable to carry an optimally sized payload. Loading a machine to less than full capacity may result in excess costs associated with unnecessary runs and the acceleration of maintenance schedules. Overloading a machine may result in increased wear and costly maintenance.
Numerous methods have been proposed for determining the mass of payloads in hauling machines. While physically weighing a machine on a scale and then deducting the weight of the machine itself may be a reliable method of measuring a payload, such an arrangement is not practical in large machines. Moreover, physically weighing a machine is generally not possible in the field.
European Patent Application Publication 0 356 067 to Kirby discloses a method of calculating the mass of a vehicle by utilizing the equation weight is equal to force divided by acceleration, that is, W=f/a, adjusted based upon calculations utilized to obtain the values for force and acceleration. Kirby proposes the measurement of acceleration based upon an inertial accelerometer, by measurements associated with a braking mechanism, or by the deformation or twisting of a drive train member measured by magnetic markers mounted on a propeller shaft of a road vehicle. The twisting of the shaft results in a delay between signals from the markers, where the time interval is proportional to the accelerating force. Kirby further proposes that force be determined from a sensor arrangement in conjunction with a time signal from a speedometer arrangement where the machine is traveling on a level ground at a constant acceleration between two speeds. Kirby indicates that resulting constants in the calculation may be evaluated in a known weight machine and eliminated by calibration such that weight of the vehicle may be calculated using the above equation.